Optical drives are commonly used to write data to the surface of a recordable medium (e.g., a CD or DVD). In this field, however, optical drive writing performance often varies due to factors such as manufacturing differences between optical drives, differences between recordable media types or brands, and differences between disc speeds, along with environmental conditions. Optical drive manufacturers allow for adjustment of laser power at the beginning of a recording session to compensate for some of these differences. In one method, each recordable medium will have a testing region, distinct from a data-carrying region, and during an Optimum Power Calibration (OPC) “test”, the testing region is written to in order to determine a better power level for writing to the media. The testing region is hereinafter referred to as the “OPC area”.
Nevertheless, the OPC area of a recordable medium may not be representative of the entire medium. For example, the thickness, sensitivity, or shape of a disc can vary as distance increases from the center of the disc. Moreover, write parameters other than power can significantly affect write performance.